So can you do differently to make sure that never happens again? How does it work, you estimated 30k and that was in writing? Then after further inspection, you realized it's gonna cost 40K, so you call the customer and he agrees? No paper work on that?

The way you described it, it doesn't seem very fair to you at all. But something doesn't add up.

Initial estimate was for around 20K. After having to replace some frame rails and a large section of the 1/4 panel it upped to around 30K.

The initial estimate was the estimate he signed and agreed upon. Verbally he agreed with the additional work, and he signed his INVOICES.

Basically, we didn't have the 30K signed and agreed upon on the estimate, just the 20, so in the judges eyes we ripped him off by luring him in for 20K and then upping it to 30K. It wasn't the estimate he agreed on, even though he gave consent for the work and paid for it.

How do we protect ourselves? Make everything into an estimate first, both parties have to sign the estimate, and then run an invoice.

Lesson learned, but still pretty lame that we got screwed over like that.